Friction clutch



Patented Apr. 2, 1940 UNITED STATES PATENT OFFICEl j Fiuc'rroN CLUTCH william' s.- wom-am, Dayton, ohio, assignmto General Motors- Corporation, Detroit, Mich.,y a corporationof Delaware Application February 27, 1939, Serial No. 258,641

2 Claims.

5 ries a flywheel and between it and a so-called pressure plate L,which rotates with the flywheelv there is gripped a driven plate carried by the transmissionlshaft. I'he present invention is concerned with an improved form of driven plate in such an assembly.

An object of the invention is to produce al driven plate having axially resilient parts to insure smooth engagement when the pressure plate is moved toward the flywheel. Other objects l5 such as efficiency in operation and simplicity and economy in production are sought to be obtained by the novel structure hereinafter described.

The invention is shown on the accompanying drawing wherein: Figure 1 is a transverse section through a part of the clutch enclosed in the usual housing.

Figure 2 is a view in elevation, partly broken away.

Figure 3 is a section on line 3--3 of Figure 2. Figure 4 is a section on line 4-4 of Figure 2. Figure 5 is a section corresponding to Figure 4 but having the parts displaced from the relation shown in Figurevi.

Figure 6 is a section on line 6--6 of Figure 2. Figure 'I is a section like that of Figure 6 but having the parts displaced from the positions they occupy in Figure 6.

On the drawing, numeral I I represents a housing for the clutch. end is an engine shaft I3 carrying a ywheel I5. Entering the housing from the opposite end is a driven shaft I'I, this being the input shaft of the transmission. Driven shaft I1 carries for rotation therewith a hub I9. A driven plate 40 designated as a whole by numeral 2l is connected to the hubby coil springs 23 which transmit the torque between plate 2l and hub I9. ".lhis spring arrangement requires no specific description inasmuch as no novelty is claimed for it. The pressure plate 25 is adapted to be moved toward the flywheel and to grip the driven plate by any preferred form of clutch engaging spring 26. The pressure plate is withdrawn from the flywheel by the use of a sleeve 21 concentric with l shaft I'I. The sleeve is adapted to be moved toward the left, Figure 1, by any convenient instrumentality such as the usual clutch throwout lever. The movement of the sleeve is transmited through levers or :ungers 29 which flngers are fulcrumed to a clutch cover 30 at 3l. Rotation Entering the housing at one' of the ngers operate to withdraw the pressure plate 25, the fingers being connected to pressure plate lugs 35 by suitable connections designated as a whole by numeral 33.

The invention resides in the details of the 6 driven plate. This plate has a plurality of radial slots marked 31 from the inner ends of each of which is a circumferential slot 39 whereby the marginal wall of the plate is provided with a plurality of circumferentially extending tongues 10 4I. To the root of each tongue, rivets I3 secure la friction facing 45 on one side-the flywheel side-of the driven plate. A second facing 41 is secured to the pressure plate side of the driven plate and is attached thereto by rivets I9 ex- 1 tending through the tips 5I of the circumferential tongues. Each facing has apertures as at 53 to provide access to the rivets which secure the other facing.

From Figure 3 it will be seen that the root por- $0 tion of each tongue lies in the plane of the plate but that the tips of the tongues are deected f rom that plane toward the pressure plate. This result is obtained by bending the tongue circumferentially as perhaps best shown by Figure 4. z5 Obviously when the pressure plate is in clutch engaging position this bend is flattened and, in the act of being flattened, it offers resilient resistance to the main clutch engaging spring. It thus insures a gradual engagement of the clutch 80 members and prevents the grabby action which results from a sudden gripping of the driven plate when the main spring is permitted to push the pressure plate toward the flywheel. To further cushion the action of the main clutch spring, a5 each circumferential tongue is formed with several radial slots extending from the marginal edge inwardly and partly across the tongue. These slots form secondary tongues marked 55, 51, 59 and 6I. 'I'he secondary tongues are 40 twisted along radial lines so that one radial edge of each tongue lies adjacent one facing and its other radial edge lies adjacent the other facing. If desired the twist may be in the same direction in each tongue although I prefer to reversely 45 twist one or more of these secondary tongues. It will be seen that the direction of twist given secondary tongue is opposite to that given the others. Also, and in order to introduce the resilient resistance of the tongues successively, 5I

one or more may be twisted sufficiently to space the facings to an extent greater than the twists of the other tongues are capable of spacing them. It will be seen that the tongues 55 and -|51 are spreading the facings and in contact with both 55 while the tongues Il and Il have clearances between their ed'ges and the i'acings, the clearances of tongue 6l being greater than those of tongue tl. In this way the resilient resistance comes into operation in successive steps.

It may be added that although the segmental tongues are shown as integral parts of the driven plate they might, if desired, be made as separate segments and secured as by riveting to the driven plate.

By the constnuction described above, the objects oi.' the invention hereinbefore set forth are accomplished by a structure which is both emcient and comparatively inexpensive.

I claim:

1. In a clutch, a driven plate, said plate having a plurality of marginal circumierentially extending tongues, the root and tip of each tongue being axially spaced, opposite i'acings secured to said plate, one facing secured to the roots of the tongues and the other secured to the tipsol.' the tongues, each oi' said tongues having a plurality of radial slots extending from the outer margin and part way across the tongues forming secondary radially extending tongues, each secondary tongue being twisted along a radial vline so that its marginal e g es lie adjacent opposite i'acings.

2. In a clutch. a driven plate, said plate having a plurality oi' marginal circumierentially extend.- ing tongues, the root and tip of each tongue being axially spaced, opposite facings secured to said plate. one facing secured to the roots oi' the tongues and theother secured to the tips of thetongues. each of said tongues having a plurality oi' radial slots extending from the outer margin and part way across the tongues forming secondary radially extending tongues, each secondary tongue being twisted along a radial line so that its marginal edges lie adjacent opposite facings, the extent of twisting being lreater in the case of certain tongues than in the case oi' others to produce a step by step resilient resistance to the attening of the plate.

WILLIAM S. WOLFRAM. 

